Catalytic process for polymerizaing ethylenically unsaturated hydrocarbons



aired rates Pater Ofilice 3,ii46,268 Patented July 24, 1962 The present invention relates to an improved polymerization process and, particularly, to such a process utilizing a novel catalyst system for polymerizing olefins to high molecular weight polymers. Still more particularly, the invention relates to such a process using a catalyst system that is advantageously soluble in conventional reaction media employed for polymerizing olefins and is highly stable against objectionable hydrolysis and thermal decomposition.

In the process embodied herein, the catalyst system comprises (1) a suitable reducing agent and (2) a compound of the formula wherein M is a metal from groups IVb, Vb and VII: of the periodic table, such as Ti to Zr+ to Hf to V+ to Nb+ to and Ta+ to M is selected from the group consisting of Si, Ge, Sn and Pb, y is the valence of the metal M, and R R and R is a hydrocarbon radical, e.g., alkyl, aralkyl, aryl, cycloalkyl, etc., and preferably an alkyl radical such as one containing from one to eight carbon atoms and specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-amyl, isoamyl, n-hexyl, n-octyl, Z-ethylhexyl, etc., and aryl radicals such as phenyl, p-tolyl, and the like.

Specific compounds falling within the scope of the aforesaid structural formula include tetrakis(trimethylsiloxy) titanium, Ti[OSi(CH tetrakis(trimethylsiloxy)-zirconium, tetrakis(triphenylsiloxy) vanadium, pentakis(trimethylsiloxy) tantalum, tetrakis(triphenylstannoxy) titanium, Ti[OSn(C I-I and others.

Compounds, other than the reducing agent, embodied for use as a catalyst component may, for example, be prepared by the method of English and Sommer, J.A.C.S. 77, 170 (1955), and illustrated by preparation of tetrakis- (trimethylsiloxy)titanium by reacting trimethylsilanol with titanium tetrachloride; by the method of Zeitler and Brown, J.A.C.S. 79, 4616 (1957) showing preparation of tetrakis (triphenylsiloxy) titanium by reacting triphenylsilanol with tetrabutoxytitanium; and still other compounds, such as those in which M is vanadium may be prepared by reacting an appropriate alkali metal triorganosilanolate or stannolate with, for example, vanadium tetrahalide in accordance with the procedure of Tatlock and Rochow, J. Am. Chem. Soc. 77, 170 (1955), and, forexample, the reaction of sodium triphenylsilanol or sodium trimethylsilanol with vanadium tetrachloride to prepare, respectively, tetrakis-(triphenylsiloxy) vanadium and tetrakis-(trimethylsiloxy) vanadium.

In reference to the reducing agent that is one component of the catalyst system embodied herein, particularly suitable and preferred are the alkylaluminum halides,

such as dialkylaluminum halides, alkylaluminum dihalides,

and mixtures thereof generally called alkylaluminum ses quihalides. Thus, embodied for use herein are ethylaluminum sesquibromide, ethylaluminum sesquichloride,

methylaluminum dibromide, dimethylaluminum bromide,

methylaluminum dichloride, dimethylaluminum chloride, butylaluminum dibromide, dibutyl aluminum chloride, hexylaluminum dibromide, dihexylaluminum bromide, and similar alkylaluminum halides and mixtures thereof. Still other reducing agents embodied for use herein are strong reducing agents such as alkali metals (e.g., sodium), alkaline earth metals (e.g., magnesium, calcium), organoalkali compounds (e.g., alkylsodium), organometallic compounds (e.g., trialkylaluminum), and the like with further specific examples including tripropylaluminum, triisobutylaluminum, tri-n-decylaluminum, butyl magnesium chloride, dibutyl magnesium, metal hydrides such as lithium hydride, magnesium hydride, etc.

Reaction conditions at which the polymerization may be carried out with the novel catalyst system include the following:

Temperature From 120 C. to 300 0.,

preferably 50 to 250 C.

Pressure Subatmospheric to 3000 atmospheres, preferably atmospheric to 200 atmos- Ratio of catalyst components pheres.

(mol ratio of reducing agent:

M-contarning compound) 0.1260 50 1, preferably 1 to Total catalyst concentration (based on weight of monomer to be polymerized) 0.005 to 10%.

The compounds which may be polymerized according to the present invention consist generally of hydrocarbons, such as the olefins containing 2 to 16 carbon atoms. Specific examples of such hydrocarbons include ethylene, propylene, butene-l, pentene-1, hexene-l, 4-methyl-pentene-l, butadiene, isoprene, styrene, methylstyrene, etc. Mixtures thereof, as for example mixtures of ethylene and butene-l, may be used for copolymerization with the catalyst system embodied herein.

The polymerization reaction is carried out in batch, semi-continuous or continuous operation. Most conveniently, and in preferred embodiments, the process at lower temperature operations is carried out in a diluent or liquid reaction medium, the amount not being unduly critical but it should be at least sufiicient to permit eifective agitation and preferably to hold the major portion of the polymer in solution.

Suitable organic media include aliphatic alkanes or cycloalkanes such as pentane, hexane, heptane, cyclohexanes; hydrogenated aromatics such as tetrahydronaphthalene, high molecular weight liquid paraflins which are liquid at the reaction temperature; aromatics such as benzene, toluene, xylene, halogenated aromatics such as chlorobenzene, chloronaphthalene, etc. Other reaction media include ethylbenzene, isopropylbenzene, ethyltoluene, n-propyl benzene, diethylbenzenes, monoand dialkyl naphthalene, n-pentane, n-octane, isooctane, methylcyclohexane, tetralin, decalin, and other inert liquid hydro carbons. In carrying out the polymerization reaction at relatively high pressures, such as at one thousand atmospheres and above, it may be carried out in the absence or substantial absence of such reaction media and, in such instance, the need for solvent recovery systems, etc., may be obviated.

It is preferred that the reaction medium that is used be essentially free of impurities which may react to destroy catalyst activity or which copolymerize with the olefinic hydrocarbon; that is, appreciable quantities of material such as carbon dioxide, oxygen and acetylenic compounds should preferably be absent.

For this process, the polymerizable hydrocarbons may be used in substantially pure form or there may be used a mixture containing major quantities thereof, provided no impurities are present in substantial amounts to destroy the catalyst and/or contaminate the polymer product. For instance, ethylene obtained by the cracking of hydrocarbon streams is satisfactory if acetylenic and oxygenated materials are not present in more than trace amounts.

In carrying out the herein described polymerization process, it is preferable and highly desirable to maintain the polymerization zone free of extraneous gases. This can be done by keeping the reaction blanketed at all times with an inert gas, for example, operating with an inert gas such as nitrogen, argon or helium. Preferably, the reactor and its contents are blanketed with the polymeriza-ble sub- Example 2 In another run, the polymerization of ethylene was carried out using V[OSi(C H and diethylaluminum chloride as the combination catalyst. In such a run,

Stance F to avcfid unnecessary dilution of 5 500 ml. of preheated decalin was charged to the reacthfi reactor contents with l f tor and the temperature adjusted to 125 C. The re- In order to further describe the nvention, the following actor Contents, 2.1 m1. of a 0.133 M- decaun Solution of examples set forth specific embodiments of catalyst sys- H Alcl was added followed b O 085 millimole of terns embodied herein for polymerizing ethylene to high H di 1 d 90 d Aft molecular weight polymers. For the examples set forth, 1O V[OS,1( 6 5)3]4 F W m m o eca er the reducing agent component of the catalyst System 30 minutes of reaction at an ethylene pressure mamtained was ethyl aluminum sesquichloride (a 1:1 mixture of at 60 Hg grams of elhylene was f A1(C5H2)C12 and 1( 1 i h l l i The product was isolated and purified as described in chloride and the other component was Ti[OSi(CH EXample 1 Y Z61 ams of a tough: Yvnlte P y V[OSi(C H or Ti[OSi (C H The following tabulation sets forth additional data per- In each of the examples, the polymerization was carried taming to the run of Example 2.

AW tide? i se 1 3? ltiiifii? ggggg il i iii gg ggg g gg gggg oi iifiitc fifififid grams (CgHQzAlCl-igrams V[OSi(CsH5)3]4 7 0.28 3.3 2.57 260 2.61 tough, white solid.

out in a three-necked glass reaction flask equipped with Example 3 a high speed stirrer thermometer, mercury manometer for In another run, ethylene was polymerized using a cam reading reactor pressure, and feed lines supplying purified lyst combination f Ti[OSi(C H and triethylalumiethylene and decahydronaphthalene. The ethylene was mum. In Such a mm, 300 of dacafin was introduced Supplied through a Pressure reducmg valve on a demand into a one liter stirred pressure autoclave previously basis during the polymerization to maintain a constant flushed with pure nitrogen The contents of the flask ethylene Pressure in the reactor (60 mm g gauge) were then heated to 180 C. under nitrogen and, after The amount i ethylene absorbed was determmed F releasing the pressure in the autoclave, 5.72 grams (0.005 the pressure drop observed at constant temperature 111 a mole) of THOSKCGHshh dispersed in 20 m1 of decalin P-P tank of known volume was added, followed by addition of 13 ml. of d 0.5 M m l 1 4 sroklution 01f triethylaluminurg t(0.57610 gram, 0.0035 trlrliolle). 0 e au oc ave was r ressure r o .s. 1.g. w1 e y ene w of decahydronaphthalene. (hell/[ed to and the polymerizat ion carried out fit one hour and ten 125. m a 250 m" a solution 9- minutes, the autoclave being repressured to 500 p.s.i.g. hydronaphthalene) of the ethylaluminum sesqurchlo-ride each time it fell to 400 P Sig The tsmperature of the was added in amount sufiicient to provide the concentra- Polymerization reaction [ganged m C At tion shown for each run in the following tabulation and, the n of the o1 merization reaction the viscolls re after an elapse of 1 /2 minutes, a 0.1 M solution of tetraa d t p 1 h d f 1 kis(trimethylsiloxy) titanium was added to provide the cum pm 110 was Sc arge. mm t e autoc ave mm amount thereof shown for each run. After such addition an excess of Water Product: when cool w of catalyst components, the polymerization was conducted wnected treated Y :hPptane mechamfial at an ethylene pressure of 60 mm. Hg gauge, at 0 Q blender to remove decalin, agaln collected, treated twice for 20 minutes, whereupon tha viscous Solution of the with acetone in the blender, and finally collected and dried polymeric product was withdrawn from the reactor and at 5 P Vacuum- The dried Polymfinc Product diluted with an equal volume of acetone. The solid poly- Obtalned Wglghad grams, Corresponding to yiald of mer was collected by filtration, boiled 10 minutes in each 25 moles of Polyethylene P mole of iotal Catalystof three successive portions of a solution of one part by While there are a ve d sclosed but a limited number volume of concentrated HCl and two parts by volume or isopropyl alcohol, then boiled 10 minutes in each of three portions of isopropyl alcohol, washed with acetone, and dried in a vacuum oven at C. to constant weight.

of embodiments of the process of the invention herein presented, it is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is desired therefore that only such 1 Relative viscosity of a 0.1 weight percent solution in decahydronaphthalene at 0.

B ASTM D-1238. 3 Under compression at 66 p.s.i.

limitations be imposed on the appended claims as are stated therein.

What is claimed is:

1. A polymerization process which comprises contacting a lower molecular weight ethylenically unsaturated hydrocarbon with a combination catalyst comprising (1) a reducing agent from the group consisting of trialkylaluminum and alkylaluminum halides and (2) a compound of the formula wherein M is a metal from groups IVb and Vb of the periodic table, M is a member from the group consisting of Si and Sn, y is the valence of M, and R R and R is a hydrocarbon radical to produce a normally solid polymer of said unsaturated hydrocarbon.

2. A process, as defined in claim 1, wherein M is a member from the group consisting of tetravalent vanadium and tetravalent titanium and M is silicon.

3. A process, as defined in claim 1, wherein the reducing agent is an alkyl aluminum halide.

4. A process, as defined in claim 1, wherein R R and R is methyl.

5. A process, as defined in claim 1, wherein R R and R is phenyl.

6. A polymerization process which comprises contacting a lower molecular weight monoolefinic hydrocarbon at from -120 to 300 C. with from about 0.005 to about 10%, based on the weight of the monoolefinic hydrocarbon, of a combination catalyst comprising (1) a reducing agent from the group consisting of tn'alkylaluminum and alkylaluminum halides and (2) a compound of the formula wherein M is a metal from groups IVb and Vb of the periodic table, M is a member from the group consisting of Si, Sn, y is the valence of M and R R and R is a hydrocarbon radical in which the mole ratio of .the reducing agent to said compound is 0.1 to 50:1 to produce a normally solid polymer of said monoolefinic hydrocarbon.

7. A process, as defined in claim 6, wherein the monoolefinic hydrocarbon is ethylene.

8. A process, as defined in claim 6, wherein the polymerization reaction is canied out in presence of an inert liquid reaction medium.

9. A process, as defined in claim 6, wherein the com pound is from the group consisting of Ti[OSi(CH 6 5)3]4 6 5)3]4- References Cited in the file of this patent UNITED STATES PATENTS 2,938,000 Wanless May 24, 1960 5 FOREIGN PATENTS 534,792 Belgium Jan. 31, 1955 OTHER REFERENCES English et al.: J. Am. Chem. Soc. 77, January 5, 1955, 30 p. 170. 

1. A POLYMERIZATION PROCESS WHICH COMPRISES CONTACTING A LOWER MOLECULAR WEIGHT ETHYLENICALLY UNSATURATED HYDROCARBON WITH A COMBINATION CATALYST COMPRISING (1) A REDUCING AGENT FROM THE GROUP CONSISTING OF TRIALKYLALUMINUM AND ALKYLALUMINUM HALIDES AND (2) A COMPOUND OF THE FORMULA 